Excimer laser annealing of perovskite thin films: morphology and gas-sensor properties

Pulsed laser annealing was used to modify surface morphology and to enhance crystallization of amorphous films of the p-type perovskite SrFeyCo1-yO2.5+x (y=0.5). The films were prepared by the pulsed laser deposition technique on sapphire substrates. Both film deposition and film annealing was done using a KrF excimer laser (wavelength = 248 nm). The effects of laser energy and pulse number on film morphology, structure and gas-sensing properties were investigated. An amorphous film did not show any sensor response to oxygen composition changes, while the same film after 80 pulses of annealing at 100mJ/cm2 showed a fast response at 300 deg. C and 400 deg. C. In comparison to a dense crystalline film deposited at 700 deg. C, the annealed film showed a faster response to oxygen composition changes at 300 deg. C